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AnthropicClaude Fable 5VSAnthropicClaude Opus 4.8

Analysis by:the whichllmmodel Editorial Team|Updated: June 2026

Our Take

We recommend Claude Fable 5 if your workflow requires peak coding capability, or the 2.0x cheaper Claude Opus 4.8 to optimize your API budget. While both models deliver similar reasoning performance, Claude Fable 5 holds a clear lead in coding. Choose Claude Fable 5 for complex development tasks, or Claude Opus 4.8 for cost optimization.
▶WHY?
Benchmark Calculations & Evidence:
  • Coding Benchmarks: Both models were evaluated on the SWE-bench Pro benchmark. Claude Fable 5 scored 80.3%, while Claude Opus 4.8 scored 69.2%.
  • Reasoning Benchmarks: Both models were evaluated on the GPQA Diamond benchmark. Claude Fable 5 scored 94.1%, while Claude Opus 4.8 scored 93.6%.
  • Cost Efficiency: Claude Opus 4.8 pricing ($5/M input, $25/M output) is 2.0x cheaper than Claude Fable 5 ($10/M input, $50/M output).
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    Model Specs

    Claude Fable 5

    Website

    Benchmarks & Scores

    Coding (swe-bench-pro)Winner (+11.1%)
    80.3%

    complex codebases, multi-file repositories, and architectural planning

    Reasoning (gpqa-diamond)Winner (+0.5%)
    94.1%

    graduate-level science QA

    Cost & Context

    Cost (per 1M tokens)
    $20.00Input: $10.00 | Output: $50.00
    Context Window
    1.05M tokens
    Model Specs

    Claude Opus 4.8

    Website

    Benchmarks & Scores

    Coding (swe-bench-pro)
    69.2%

    complex codebases, multi-file repositories, and architectural planning

    Reasoning (gpqa-diamond)
    93.6%

    graduate-level science QA

    Cost & Context

    Cost (per 1M tokens)2.0x cheaper
    $10.00Input: $5.00 | Output: $25.00
    Context Window
    1.05M tokens
    Read our data collection methodology

    Frequently Asked Questions about Claude Fable 5 vs Claude Opus 4.8

    Claude Opus 4.8 is cheaper than Claude Fable 5. Claude Opus 4.8 has a blended cost of $10.00/1M tokens, which is about 2.0x cheaper than Claude Fable 5 at $20.00/1M tokens.

    Claude Fable 5 is better for coding tasks on this benchmark. It scores 80.3% on swe-bench-pro (complex codebases, multi-file repositories, and architectural planning) compared to Claude Opus 4.8 which scores 69.2%.

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